Researchers recruited 27 semi-professional rugby players. All were very young, close to eighteen years old, and also pretty strong. The average parallel squat in the group was over 400 pounds for a set of three reps. Researchers started by measuring each player’s maximum vertical jump. Then each player performed three squats at his 3RM. Some players performed quarter-squats and some performed parallel squats. Then everyone was tested again in the vertical jump.

Both groups saw an increased vertical jump after the squats, but the parallel squat group increased their jump height the most. In fact, the parallel squat group enjoyed 30% more improvement than the quarter squat group. The parallel squat group jumped over 12% higher than their baseline. What would an extra 12% in jump height mean to you? That’s what PAP delivered in this study.

Science still can’t fully explain PAP. In this scenario, researchers think the parallel squats worked better because they stretched the gluteus maximus more than the quarter squats. But nobody really knows for sure. All we really know at this point is that PAP works.

What clues can we collect about the best ways to use PAP? Today’s study shows that parallel squats are better than quarter squats. A recent study showed that heavier loads are better than lighter loads. In fact, the closer to 1RM the better. Another study showed that deadlifts at 85% 1RM can improve sprinting, but the effect fades drastically after ten minutes. PAP can even be induced by pulling against an immovable object, as shown in yet another study.

If we crudely throw all these results together, we can come to a few conclusions. For optimum PAP we should choose a lift that mimics the explosive activity to follow, use the lift’s complete range of motion, use a load as close to 1RM as possible, and rest no more than ten minutes between the lift and the explosive activity that follows.